WebService 的常见问题

首先是写 WebMethod

WebService.cs

 　　/// <summary>
    /// 按分类和关键字查询商品
    /// </summary>
    /// <param name="categoryId"></param>
    /// <param name="keyword"></param>
    /// <returns></returns>

    [WebMethod]
    public DataTable GetGoodsByCategoryKey(string categoryId, string keyword)
    {
        string strWhere = "1=1";
        if (categoryId != "0")
        {
            string sonCategoty = Common.GetSonCategory(Util.GetInt(categoryId), "") + categoryId;
            strWhere += " AND CategoryId IN(" + sonCategoty + ")";
        }
        if (!Util.IsEmpty(keyword))
        {
            strWhere += " AND GoodsNO LIKE '%" + keyword + "%' or GoodsName LIKE '%" + keyword + "%'";
        }
      
        DataSet ds = new SQLServerDAL.A_GoodsInfo().GetDataSet(null, strWhere.ToString(), "SortIndex ASC");
        DataTable table = null;
        if (ds.Tables[0].Rows.Count > 0)
        {
            //table = Detect.ListToDataTable(PublicGoodsList(strWhere.ToString(), ds.Tables[0]));
            table = ds.Tables[0];
        }
        //Detect.GetDistinctTable(ds.Tables[0], "SpareInt2");

        return table;
    }

不要忘了引用：using Microsoft.Web.Script.Services;

然后再aspx 上写入

1 　　<asp:ScriptManager ID="ScriptManager1" runat="server">
2         <Services>
3             <asp:ServiceReference Path="http://www.cnblogs.com/WebService.asmx" />
4         </Services>
5     </asp:ScriptManager>

然后js 就可以调用了：

方法一：

 1 function searchItem()
 2         {
 3           var cat=document.getElementById('DDL_Seach_Category');
 4           var catId=cat.options[cat.selectedIndex].value;
 5           var keyword  = document.forms['theForm'].elements['keyword'].value;
 6           WebService.GetGoodsByCategoryKey(catId,keyword,
 7 　　         function(result)
 8 　　         {
 9               var sel = document.forms['theForm'].elements['result'];
10               sel.length = 0;
11 
12               /* 创建 options */
13               if(result!=null){
14                 var Text = result.dataArray.substring(0, result.dataArray.length - 1);
15                 var Table = eval(Text);　　
16   
17                 for (x = 0; x < Table.length; x++) {
18                     var Row = Table[x];
19                     var option = document.createElement("option");
20                    option.text =Row.GoodsName;
21                    option.value = Row.GoodsId;
22                     if (window.navigator.appName.toLowerCase().indexOf("microsoft") > -1) 
23                         sel.add(option);
24                     else 
25                         sel.add(option, null);
26                 }
27                 }
28                 else{
29                     alert("没有该类商品！");
30                 }
31             })
32         }

方法一有时会出现返回的 result 中没有 dataArray 的问题，导致数据显示不出来（据说是调用的的一个库的问题）

方法二：

function searchItem() {
                var cat = document.getElementById('DDL_Seach_Category');
                var catId = cat.options[cat.selectedIndex].value;
                var keyword = document.forms['theForm'].elements['keyword'].value;
                WebService.GetGoodsByCategoryKey(catId, keyword, function (result) {
                    var sel = document.forms['theForm'].elements['result'];
                    sel.length = 0;

                    /* 创建 options */
                    if (result != null) {
                        for (x = 0; x < result.rows.length; x++) {
                            var option = document.createElement("option");
                            option.text = result.rows[x].GoodsName;
                            option.value = result.rows[x].GoodsId;
                            if (window.navigator.appName.toLowerCase().indexOf("microsoft") > -1)
                                sel.add(option);
                            else
                                sel.add(option, null);
                        }
                    }
                    else {
                        alert("没有该类商品！");
                    }
                })
            }

换成方法二就解决了，如果哪位也遇到这种情况！麻烦给我说下为什么？